1. Field of the Invention
The present invention relates generally to a film magazine for sequentially presenting a plurality of film units to an exposure position, and more specifically to such a magazine having a shuttle that supports the film units for exposure and removes the exposed film units through a processing mechanism.
2. Brief Description of the Prior Art
It is well known to supply film units to cameras in multi-unit packs. The frequency with which the camera must be reloaded can be reduced by increasing the number of film units. However, this makes the pack larger and complicates the sequential positioning of the film units for exposure.
Packs that contain self-processing film units have both adavantages and disadvantages in this respect. Since many commercial self-processing film units can be processed in the daylight, the exposed film units need not be retained in the pack, but, instead, can be removed almost immediately from the camera. Therefore, it is possible to advance a stack of such film units so that successive units are located for exposure and then ejected from the camera through an exit slot. This approach is, in fact, employed in modern self-processing cameras which typically are adapted to receive packs of ten or fewer film units. When packs containing many more film units have been tried, problems have been encountered primarily because the film units are not uniform in caliper.
The lack of uniform caliper is a result of each film unit having a pouch of processing fluid at one end and a trap for excess fluid at the other end, each of which is thicker than the central, imaging section. When pressure is applied to it, the stack tends to collapse in the center and splay apart at the ends, making it difficult to both properly seat the forwardmost film unit for exposure and align it for movement through the exit slot. If increased pressures are employed in an attempt to properly seat the forwardmost film unit, the resulting frictional forces present substantial resistance to the removal of the units from the pack.
A solution to the above-mentioned problem is proposed in commonly-assigned copending U.S. patent application Ser. No. 084,474, entitled FILM PACK, filed on Oct. 15, 1979 in the name of Robert A. Sylvester, now U.S. Pat. No. 4,236,798. A shuttle plate is reciprocally mounted in the film pack. During exposure, the shuttle plate is positioned behind the forwardmost film unit to support it and to isolate the supported film unit from distorting forces transmitted through the other film units. After the exposure, lateral movement of the plate draws the supported film unit through a processing mechanism and exit slot.
The Sylvester approach provides for sequential movement of the film unit and shuttle so the shuttle moves with the film unit through the processing mechanism. The present invention is an improvement over Sylvester in that, instead of moving with the film unit through the mechanism, the shuttle follows the film unit.